Service meter MD 31; manufactured by Brown Boveri Cie.

In order to enable the signals mechanic to do funktion tests on radio sets and simple repairs, specific test sets were developed for some of the sets.

Brown Boveri developed the MD31 test device for service and alignment work on the SE-202 (SEF) radios.

• Principle: Current measurements

• None

• Wooden case

• RF indicator, measuring head MDZ31

The measuring instrument of the MD31, referred to as a galvanometer (the correct readings for different kind of measurements are stated in graduation marks (Skt)), has a range of 75 - 0 - 75 μA. It is normally bridged with a shunt resistor; when the shunt button is pressed, the shunt is interrupted and the measuring instrument deflection increases by a factor of 3½.

The service meter also includes an RF indicator: the RF energy from the transmitter is collected by its two antenna rods, rectified in a diode and passed on to the galvanometer for measurement; the RF indicator is only used to detect any RF emissions from the transmitter, the transmission output cannot be measured.

The Dummy Load MZ31 (old designation AZ31) allows more precise determination of the output power, the light from the incandescent bulb powered by the RF current excites the photocell, the voltage of which can be measured with the service meter. A calibration curve on the cabinet outside lets you estimate the output power.

The measuring head MDZ21 can be plugged into the tube socket V1, V4, V5, V7 or V8 instead of a tube and allows measurements.

Galvanometer

The MD31 service meter was designed for maintenance work and aligment on SE-202 (SEF) radios.

SE-202 /SEF: m) Testgerät MD-31

SE-202 /SEF: n) Testgerät MD-31 Instruktionen

• Pzj. station CF63, Jeep radio station CF41, technical manual, BBC with description of the alignment and diagrams, including the service instrument and accessories.